豚草Ambrosia artemisiifolia

豚草Ambrosia artemisiifolia

豚草Ambrosia artemisiifolia

中文名(Chinese Name):豚草
学名(Scientific Name):Ambrosia artemisiifolia L.
英文名(English Common Name): annual ragweed
别名(Chinese Common Name):豕草
异名(Synonym):Ambrosia elatior L.  Ambrosia artemisiifolia var. elatior (L.) Descourt.  Ambrosia glandulosa Scheele  Ambrosia monophylla (Walter) Rydb.  Ambrosia paniculata Michx.  Ambrosia chilensis Hook. & Arn.
科属(Family & Genus):菊科(Compositae)豚草属
形态特征(Description):一年生草本,高20-150厘米;茎直立,上部有圆锥状分枝,有棱,被疏生密糙毛。下部叶对生,具短叶柄,二次羽状分裂,裂片狭小,长圆形至倒披针形,全缘,有明显的中脉,上面深绿色,被细短伏毛或近无毛,背面灰绿色,被密短糙毛;上部叶互生,无柄,羽状分裂。雄头状花序半球形或卵形,径4-5毫米,具短梗,下垂,在枝端密集成总状花序。总苞宽半球形或碟形;总苞片全部结合,无肋,边缘具波状圆齿,稍被糙伏毛。花托具刚毛状托片;每个头状花序有10-15个不育的小花;花冠淡黄色,长2毫米,有短管部,上部钟状,有宽裂片;花药卵圆形;花柱不分裂,顶端膨大成画笔状。雌头状花序无花序梗,在雄头花序下面或在下部叶腋单生,或2-3个密集成团伞状,有1个无被能育的雌花,总苞闭合,具结合的总苞片,倒卵形或卵状长圆形,长4-5毫米,宽约2毫米,顶端有围裹花柱的圆锥状嘴部,在顶部以下有4-6个尖刺,稍被糙毛;花柱2深裂,丝状,伸出总苞的嘴部。瘦果倒卵形,无毛,藏于坚硬的总苞中。花期8-9月,果期9-10月。
分布(Distribution):原产北美,在我国部分地区已归化。
用途(Use):
引自中国植物志英文版FOC Vol. 20-21 Page 876, 877
Ambrosia artemisiifolia Linnaeus, Sp. Pl. 2: 988. 1753.
豚草 tun cao| Asteraceae  | Ambrosia
Ambrosia artemisiifolia var. elatior (Linnaeus) Descourtilz; A. elatior Linnaeus.
Annuals, 20-150 cm. Stems erect. Leaves opposite and alternate; petiole 2.5-3.5(-6) cm; blade deltate to lanceolate or elliptic, 2.5-5.5(-9) × 2-3(-5) cm, pinnately 1- or 2-lobed, abaxially sparsely pilosulose to strigillose, adaxially strigillose, both surfaces gland-dotted, base cuneate, ultimate margin entire or toothed. Female capitula clustered, proximal to male; floret 1. Male capitula: peduncles 0.5-1.5 mm; involucres shallowly cup-shaped (usually without black veins), 2-3 mm in diam., glabrous or hispid to pilosulose; florets 12-20. Burs ± globose to pyriform, 2-3 mm, ± pilosulose, spines or tubercles 3-5, near middle or apex, conical to acerose, 0.1-0.5 mm, tips straight. Fl. Jul-Oct, fr. Sep-Oct. 2n = 34, 36.
Introduced noxious weed of wet to dry soils; below 1000 m. Widely distributed in China [native to Central and North America; introduced and widely distributed in Asia and Europe].
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